EP0818758B1 - Device for testing the validity of coins, tokens or other flat, metallic objects - Google Patents

Description

The invention relates to a device for checking the authenticity of coins, tokens or other flat metallic objects referred to in the preamble of claim 1 Art.

Such coin validators are suitable, for example, for the identification of coins in telephone sets, vending machines, counters for measuring energy, etc.

A device for checking the authenticity of coins, tokens or other flat metallic objects according to the preamble of claim 1 is known from US Pat. No. 4,509,633. The device comprises light barriers for determining the chord length and an inductive sensor for measuring the alloy composition of the coins.

From the European patent EP 694 888 a device for checking the authenticity of coins, tokens or other flat metallic objects is known in which the chord length of the coin is determined by means of two light barriers with high accuracy by optical means. However, this optical measuring principle is unable to distinguish metallic and non-metallic coins.

From the European patent application EP 704 825 a device for checking the authenticity of coins, tokens or other flat metallic objects is known in which the alloy composition of the coin is determined by means of an inductive sensor. For a coin with a large diameter, the edge of the coin is outside the sensitivity range of the inductive sensor. The coin material along the coin edge therefore contributes nothing to the measurement result.

Both in a device according to the teaching of US Pat. No. 4,509,633 and in a device according to the teaching of a combination of the two last-mentioned documents, it is not possible to recognize coins which have an inner region of a first alloy and an area running along the edge with a second region Alloy exhibit. Similarly, counterfeits where a small coin simulates a larger coin by applying a cardboard or plastic edge can not be distinguished from real coins.

In one known from European Patent EP 543 200 means for checking the authenticity of coins, an inductive sensor is provided in the form of a coil which is disposed below the path of the coin channel and their magnetic field through the bottom of the Munzkanals through perpendicular to the on the Track rolling coin is directed so that the edge of the coin is magnetically captured. This solution requires an additional sensor.

The invention has for its object to provide a device for testing the authenticity of coins, tokens or other flat metallic objects, in which the aforementioned disadvantages are eliminated.

The invention consists in the features specified in claim 1. Advantageous embodiments result from the dependent claims.

According to the invention, the detection of a new measured value of the inductive sensor is proposed, which serves as a criterion for the acceptance or rejection of the coin, which can be used in addition to the existing criteria or instead of another criterion: The signal of the inductive sensor is at one time detected at the edge of the rolling coin passes the sensitive zone of the inductive sensor.

In a preferred embodiment, the inductive sensor is located between two light barriers. As the coin passes, the inductive sensor signal is latched as a function of time as a series of measurements. From the time points marking the beginning and the end of the darkening of the light barriers, the chord length or the diameter of the coin is determined according to the laws of physical motion. Subsequently, the time at which the edge of the coin was in the center of the inductive sensor and the signal of the inductive sensor at this time from the stored measured values by interpolation is calculated. The measured value thus obtained serves as a criterion for acceptance or rejection of the coin.

In another variant, the coin passes at least one before or after the inductive sensor in a suitably selected distance arranged light barrier and the output from the light barrier signal triggers the detection of the signal of the inductive sensor directly.

In a further variant of the inductive sensor is arranged so that its sensitive zone is arranged approximately at the level of the bottom of the coin channel. The edge of the coins then always passes through the center and the coin's alloy composition can be measured in a known manner.

Embodiments of the invention will be explained in more detail with reference to the drawing.

Fig. 1

Eine Einrichtung zur Prüfung der Echtheit von Münzen mit zwei Lichtschranken und einem induktiven Sensor,

Fig. 2

das Signal des induktiven Sensors in Funktion der Zeit,

Fig. 3

eine weitere Einrichtung zur Prüfung der Echtheit von Münzen,

Fig. 4

eine Einrichtung mit einem speziell angeordneten induktiven Sensor,

Fig. 5

eine Einrichtung zur Kontrolle der elektrischen Leitfähigkeit der Münzen, und

Fig. 6

eine Einrichtung mit einem akustischen Sensor.

Show it:

Fig. 1

A device for checking the authenticity of coins with two photocells and an inductive sensor,

Fig. 2

the signal of the inductive sensor as a function of time,

Fig. 3

another device for checking the authenticity of coins,

Fig. 4

a device with a specially arranged inductive sensor,

Fig. 5

a device for controlling the electrical conductivity of coins, and

Fig. 6

a device with an acoustic sensor.

Fig. 1 shows a device for checking the authenticity of coins or tokens or other flat metallic objects, which will be referred to below as a coin. The device has in a conventional manner a coin channel K, two light barriers L1 and L2, an inductive sensor S1 and electronic means E for detecting and evaluating the output from the light barriers L1 and L2 and the sensor S 1 electrical signals. The sensor S1 is advantageously arranged between the two light barriers L 1 and L 2. In the area from the coin inlet to the first light barrier L 1 is the Coin channel K, for example, according to the teaching of European patent EP 710 935 designed and provided with energy-absorbing elements that a hopping or jumping of the coin M between the two light barriers L1 and L2 does not normally occur. In the region between the two light barriers L1 and L2 of the coin channel K is formed as an inclined plane SE, which is inclined relative to the horizontal H by the angle Θ. On the inclined plane SE between the two light barriers L1 and L2, the coin M now moves downwards at a constant acceleration, which occurs as a result of the gravitational force and frictional forces. The movement may be non-gliding, gliding without rollers or a combination of rollers and glides. The light barriers L1 and L2 are arranged above the inclined plane SE at a predetermined, equal height h and at a predetermined distance L. The distance traveled by the coin M on the plane SE at time t is designated by the coordinate x (t).

wobei a die als konstant angenommene Beschleunigung und v₀ die Anfangsgeschwindigkeit der Münze M zur Zeit t₀ bezeichnen.When rolling along the coin channel K, the coin M successively covers the two light barriers L 1 and L2. The electronic means E detect the times t ₀ - t ₃ , wherein the times t ₀ and t ₁ the beginning or the end of covering the first light barrier L1 and the times t ₂ and t ₃ the beginning or the end of the covering the second photocell L2. The zero points x ₀ and t _{0 of} the coordinate axis x and the time t are selected such that x ₀ = 0 and t ₀ = 0, respectively, when the coin M begins to cover the first light barrier L1. European patent EP 694 888 now shows that from the measured times t ₀ -t ₃ the coordinate x (t) can be calculated for an arbitrary time t, eg according to the equation $$\mathrm{x}\left(\mathrm{t}\right)\mathrm{=}\mathrm{½a}{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">t</figure-callout>}}^{\mathrm{2}}\mathrm{+}{\mathrm{v}}_{\mathrm{0}}\mathrm{t}\mathrm{=}\mathrm{<figure-callout\; id="1"\; label="L\; \; t"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L\; </figure-callout>}\frac{{\mathrm{t}}_{}}{}\frac{{\mathrm{}}_{\mathrm{1}}\mathrm{+}{\mathrm{t}}_{\mathrm{2}}\mathrm{-}{\mathrm{t}}_{\mathrm{3}}}{\mathrm{(}{\mathrm{<figure-callout\; id="3"\; label="t"\; filenames="imgf0002.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{3}}^{\mathrm{2}}\mathrm{-}{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{1}}^{\mathrm{2}}\mathrm{)}{\mathrm{t}}_2\mathrm{-}\left({\mathrm{t}}_{\mathrm{3}}\mathrm{-}{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{1}}\right){\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{2}}^{\mathrm{2}}}\mathrm{t}\mathrm{*}\left(\mathrm{t}\mathrm{-}{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{2}}\right)\mathrm{+}\frac{\mathrm{<figure-callout\; id="2"\; label="L\; t"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">L\; </figure-callout>}}{{\mathrm{t}}_{}}\mathrm{t}\mathrm{.}$$

where a denotes the acceleration assumed to be constant and v ₀ the initial velocity of the coin M at time t ₀ .

und $$\mathrm{D}\mathrm{=}\frac{{\mathrm{B}}^{\mathrm{2}}\mathrm{+}\mathrm{4}{\mathrm{h}}^{\mathrm{2}}}{\mathrm{4}\mathrm{h}}\mathrm{,}$$

entweder durch ihre Sehnenlänge B oder ihren Durchmesser D charakterisiert werden.The coin M can according to the equations $$\mathrm{B}\mathrm{=}\mathrm{L}\frac{\mathrm{(}{\mathrm{t}}_{\mathrm{2}}\mathrm{-}{\mathrm{t}}_{\mathrm{3}}\mathrm{)}{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{1}}^{\mathrm{2}}\mathrm{+}\left({\mathrm{<figure-callout\; id="3"\; label="t"\; filenames="imgf0002.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{3}}^{\mathrm{2}}\mathrm{-}{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{2}}^{\mathrm{2}}\right){\mathrm{t}}_{\mathrm{1}}}{\left({\mathrm{<figure-callout\; id="3"\; label="t"\; filenames="imgf0002.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{3}}^{\mathrm{2}}\mathrm{-}{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{1}}^{\mathrm{2}}\right){\mathrm{t}}_{\mathrm{2}}\mathrm{-}\left({\mathrm{t}}_{\mathrm{3}}\mathrm{-}{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{1}}\right){\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{2}}^{\mathrm{2}}}$$

and $$\mathrm{D}\mathrm{=}\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">B</figure-callout>}}^{\mathrm{2}}\mathrm{+}\mathrm{4}{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">H</figure-callout>}}^{\mathrm{2}}}{\mathrm{4}\mathrm{H}}\mathrm{.}$$

be characterized either by their chord length B or their diameter D.

When rolling the coin M along the coin channel K, the electronic means E also detect the signal s (t) output by the inductive sensor S1 and store it as a digital sequence of discrete values s _i (t = τ _i ), the index i eg Takes values from 1 to 64 and τ _{i is} given by τ _i = t ₀ + i * Δt. The time period Δt is a suitably predetermined amount.

FIG. 2 shows the signal s (t) of the inductive sensor S1 (FIG. 1). Shown are times t ₄ and t ₅ . The crosses mark on the signal curve s (t) the values s _i (t = τ _i ) detected during the passage of the coin M and stored in the sequence f. At time t ₄ , the leading edge of the coin M passes through the center of the inductive sensor S1 and the coin M is in place $$\mathrm{x}\left({\mathrm{t}}_{}\right)$$$$\left({\mathrm{}}_{\mathrm{4}}\right)\mathrm{=}{\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="imgf0001.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{1}}\mathrm{,}$$

The location w ₁ depends on the diameter D or the chord length B of the coin M: $${\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="imgf0001.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{1}}\mathrm{=}{\mathrm{w}}_{\mathrm{1}}\left(\mathrm{D}\right)\mathrm{=}{\mathrm{w}}_{\mathrm{1}}\left(\mathrm{B}\right)\mathrm{,}$$

The value w ₁ (B) can be taken from a table after the determination of the chord length B according to the equation (3). Subsequently, the time t ₄ can be calculated from equations (1) and (4) and-then-determined from the sequence f by interpolation of the measured value s (t ₄ ). In this way, therefore, let the signal of the inductive sensor S1 hold exactly when the coin M with respect to the inductive sensor S1 occupies a predetermined geometric position.

In an analogous manner, the measured value s (t ₅ ) can be determined when the rear edge of the coin M passes through the center of the inductive sensor S1, this position being defined by the location w ₂ .

It depends on the totality of the types of coins to be tested whether the locations w ₁ (B) and w ₂ (B) are to be stored in a table, or whether a common value w ₁ and / or w ₂ can be used for all coin types ,

With the formula (1), the timing at which the edge of the coin M passes the center of the inductive sensor S1 can be calculated with high accuracy. The formula (1) could, of course, be replaced by a less accurate equation which, instead of assuming a constant acceleration a of the coin M during the passage between the light barriers L1 and L2, from the times t ₀ to t _3, an average velocity of the coin M determined and calculated from the desired time t ₄ or t ₅ with lower accuracy.

According to the teaching of EP 704 825, the maximum s _M (FIG. 2) of the signal s (t) also serves as a criterion for the acceptance or rejection of the coin M.

FIG. 3 shows a further device with at least the light barrier L1 and the inductive sensor S1. The distance d ₁ between the light barrier L1 and the inductive sensor S1 is adapted to the coins M1 of a special type such that the edge of the coin M1 is approximately in the center of the inductive sensor S1, when the coin M1 no longer covers the light barrier L1 ie at time t ₁ . In this arrangement, the light barrier L1 triggers the detection of the value of the signal s (t ₁ ) at time t ₁ directly during the passage of the coin M1 and the latching of the signal s (t) as Episode f can be omitted.

The same principle can be applied to the light barrier L2, which is arranged in the direction of the coin after the inductive sensor S1. The distance d ₂ between the light barrier L2 and the inductive sensor S1 may be equal to the distance d ₁ or, adapted to the coins M2 of a second kind, different therefrom.

The arrangement of the light barriers L1 and L2 in suitably predetermined distances d ₁ and d ₂ from the inductive sensor S1, the intermediate storage of the signal s (t) can be omitted in this simple solution because the light barriers L1 and L2, the direct detection of two at least certain coins M1 and M2 restrictively characterizing values of the signal s (t).

The proposed devices are particularly suitable for testing coins whose edge consists of a material with a different alloy composition as its center. Such coins appear optically bicoloured. An example of such a bicolor coin is the French ten-centimes coin. The inductive sensor S1 thus serves, depending on the use of the previously described solutions for determining the alloy composition of the edge or the edge and the center.

Even coins whose border has been fraudulently changed by attaching plastic or cardboard to simulate a larger diameter, are recognized by the facilities described as counterfeiting and rejected.

It is often necessary to operate the inductive sensor S1, which is in the form of a coil or a coil with an oppositely disposed metal plate, at two different frequencies f1 and f2, the coil being e.g. According to the teaching of Swiss patent application CH 869/96, both frequencies f1 and f2 can be acted upon simultaneously or the coil is subjected to the first frequency f1 and then to the second frequency f2 until the maximum of the signal s (t) is reached.

Another inductive sensor is usually provided for determining the thickness of the coin M.

4 now shows a device in which an inductive sensor S2 is arranged relative to the bottom of the coin channel K so that the center of the sensitive zone is at the height of the coin channel K or a small distance z above it, so that the Edge of each coin M is detected. The inductive sensor S2 is disposed in a side wall of the coin channel and its field 1 indicated by an arrow is laterally against the coin M, i. parallel to the axis of rotation of the coin M, directed. The signal of the inductive sensor S2 can be evaluated in a known manner, a synchronization by the light barriers L1, L2 is not required.

Fig. 5 shows another means by which it is possible to check whether the coin M fraudulently changes by adhering it to an electrically insulating material such as plastic or cardboard has been. The bottom of the coin channel K and the opposite to the vertical slightly inclined rear wall of the coin channel K are each coated with an electrically conductive layer 2 and 3, for example with metal foils. The electronic means E are arranged to measure the electrical resistance between the two layers 2 and 3. A normal coin M leads during passage at least briefly to a short circuit between the layers 2 and 3, a manipulated coin not. The occurrence of the short circuit is a necessary condition for accepting the coin M.

Fig. 6 shows a device in which the coin M impinges on a metallic plate 4, which is fixed or loose in a recess 5 of the bottom of the coin channel K is arranged. The coin channel K has, for example, the geometry described in European patent EP 710 935 and the metallic plate 4 also serves to absorb energy of the coin M. The impact leads to a true coin M to a characteristic metallic sound, by means of an acoustic sensor ie a microphone 6, detected and further processed by the electronic means E. In particular, an analysis is provided as to whether a noteworthy signal occurs in a predetermined frequency band. In a manipulated coin, the sound is dull and leads to its rejection.

Claims (2)

1. Device for testing the validity of coins, tokens or other flat metallic objects (M) comprising a channel for the object (M) tilted relatively to the horizontal (H) according to an angle Θ and an electronic device (E) capturing the moment t0 of the beginning of covering a light barrier (L1) by the object (M) passing the tilted channel as well as a further signal s(t) linked to the moment t0 used as criterion for the acceptance or the rejection of the object (M),
   characterized in that
   an inductive sensor (S1) generates the signal s(t) at passing of the object (M) and that the signal of the light barrier (L1), at the moment t0, determines the moment t4, t5 of the capture of the signal s(t) of the sensor (S1) and that the inductive sensor (S1) generates a magnetic field (1) directed laterally towards the object (M) running on the tilted channel and captures it mainly at the height of the bottom of the tilted channel or at a small distance (z) above the bottom.
2. Device according to claim 1, characterized in that the electronic device (E) also detects the moment t1 of the end of covering the light barrier (L1) by the object (M), the moment t2 of the beginning and the moment t3 of the end of covering an additional light barrier (L2), calculates the chord length (B) of the object (M) from the four moments t0, t1, t2, and t3 according to a predetermined equation and calculates the moment t4, t5 of the capture of the signal s(t) of the sensor (S1) according to an additional predetermined equation from the sequence of the moments t0, t1, t2 and t3.

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